operation status for the asteroid explorer, hayabusa2 · sampling mechanism, re-entry capsule,...

Operation status for the asteroid

explorer, Hayabusa2

October 11, 2018

JAXA Hayabusa2 Project

Topics

MASCOT separation operation report

Touchdown rehearsals and plans

Contents

Hayabusa2 mission summary & outline of mission flow Current status and schedule overview for the project. MASCOT separation operation Touchdown rehearsals and plans Future plans

ObjectiveWe will explore and sample the C-type asteroid Ryugu, which is a more primitive type than the S-type asteroid Itokawa that Hayabusa explored, and elucidate interactions between minerals, water, and organic matter in the primitive solar system. By doing so, we will learn about the origin and evolution of Earth, the oceans, and life, and maintain and develop the technologies for deep-space return exploration (as demonstrated with Hayabusa), a field in which Japan leads the world.

Features: World’s first sample return mission to a C-type asteroid. World’s first attempt at a rendezvous with an asteroid and performance of observation before and after projectile impact from an impactor. Comparison with results from Hayabusa will allow deeper understanding of the distribution, origins, and evolution of materials in the solar system.

Expected results and effects By exploring a C-type asteroid, which is rich in water and organic materials, we will clarify interactions between the building blocks of Earth and the evolution of its oceans and life, thereby developing solar system science. Japan will further its worldwide lead in this field by taking on the new challenge of obtaining samples from a crater produced by an impacting device. We will establish stable technologies for return exploration of solar-system bodies.

International positioning Japan is a leader in the field of primitive body exploration, and visiting a type-C asteroid marks a new accomplishment. This mission builds on the originality and successes of the Hayabusa mission. In addition to developing planetary science and solar system exploration technologies in Japan, this mission develops new frontiers in exploration of primitive heavenly bodies. NASA too is conducting an asteroid sample return mission, OSIRIS-REx (launch: 2016; asteroid arrival: 2018; Earth return: 2023). We will exchange samples and otherwise promote scientific exchange, and expect further scientific findings through comparison and investigation of the results from both missions.

Hayabusa 2 primary specifications Mass Approx. 609 kg Launch 3 Dec 2014 Mission Asteroid return Arrival 27 June 2018 Earth return 2020 Stay at asteroid Approx. 18 months Target body Near-Earth asteroid Ryugu Primary instruments Sampling mechanism, re-entry capsule, optical cameras, laser range-finder, scientific observation equipment (near-infrared, thermal infrared), impactor, miniature rovers.

Overview of Hayabusa2

(Illustration: Akihiro Ikeshita)

Arrival at asteroid June 27, 2018

Examine the asteroid by remote sensing observations. Next, release a small lander and rover and also obtain samples from the surface.

Use an impactor to create an artificial crater on the asteroid’s surface

Sample analysis After confirming safety, touchdown within the crater and obtain subsurface samples

Depart asteroid Nov–Dec 2019

Launch 3 Dec 2014

Earth return late 2020

Mission Flow

(Illustrations: Akihiro Ikeshita)

▲ Earth swing-by3 Dec 2015

Release impactor

Create artificial crater

1. Current project status & schedule overview

2015 2016 2017 2018 2019 2020

12 3 10 12 4 6 7 12 12

Event

Earth swing-by

Southern hemisphere station operations (CAN/MLG)

Ion engine operations ※

Arrival at Ryugu Departure from Ryugu Capsule re-entry launch

Optical navigation Solar conjunction

Schedule overview:

Current status –  MASCOT separation operation was performed between September 30 –

October 4, with MASCOT successfully separating on October 3. MASCOT then proceeded to land on the surface of Ryugu and operated for about 17 hours.

–  The next rehearsal for the first touchdown (TD1-R1-A) will be held from October 14 – 15.

2.MASCOT separation operationOperation outline:   Sept. 28 Agreement for separation received from MASCOT Project Manager,

Dr Tra-Mi Ho.  Oct 2, 11:50 (listed times are all JST): Begin descent  Oct 3, 10:57:00: MASCOT separated at an altitude of 51m.  October 4, 04:30: Declaration of mission completion received from Dr Tra-Mi Ho

(MASCOT continued to operate for 17 hours after separation  We successfully communicated with MASCOT and confirmed that MASCOT landed on the surface of Ryugu. Data acquired from the observations conducted by MASCOT instruments were transmitted to the MASCOT team (Germany) .   Confirmed that MASCOT moved via designed hop.   The operation of MASCOT itself was conducted from the German side, with about 40 people in DLR Cologne. About 5 people in CNES Toulouse supported the operation.  DSN (US Deep Space Network) level 2 support*   The acquired data is also being used as reference information for touchdown operation.

*level 2 support: = increased number of engineers (We also requested double antennas)

Altitude

Time (JST)

Home position 20km

Hovering altitude 3km

60m

51m

MASCOT separation

First contact

Rest on surface

GCP-NAV

Descent speed 40cm/s→10cm/s Decelerate at 5km altitude

Descent speed 3cm/s

Free fall without thruster

Attitude scan Hovering

Ascent speed 50cm/s

10/2, 11:50 10/3, 16:00( 1day)

Return to home position

10/3, 10:55 10:57:20 10/8, 15:00

2. MASCOT release operationOutline of MASCOT release operation sequence

Separation time©JAXA

Successful capture in 3 consecutive images by the Optical Navigation Camera – Wide angle (ONC-W2). Image time Oct. 3, 2018

1 shot 10:57:54 2 shot 10:58:04 3 shot 10:58:14Note: separation time 10:57:20

Watch here

(Image credit: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, Aizu University, AIST.)

MASCOT captured with the ONC-W2

3 image animation

2. MASCOT separation operation

(Time : JST)

2018/10/3 10:57:54


2018/10/3 10:58:04 2018/10/3 10:58:14

2. MASCOT separation operationMASCOT captured with the ONC-W2

6m

4.23m

Image capture time: Oct. 3, 2018 at 10:59:40 JST MASCOT altitude ~35m

MASCOT shadowMASCOT underside (©DLR) (Image credit: on previous page)

2. MASCOT separation operationMASCOT captured with the ONC-W2

Images from the MASCOT camera (MASCAM)

Image credit MASCOT/DLR/JAXA

Image from an altitude ~25m. The black dot in the upper right is the shadow of MASCOT.

Images from the surface of Ryugu


MASCOT landing point

The blue ‘X’ shows the estimated landing site of MASCOT.



2. MASCOT separation operationReaction in Europe

Presentation of the newest information about Hayabusa2 including MASCOT at IAC (International Astronautical Congress) in Bremen, Germany on October 5, 2018. Photo by Dr. Hikaru Yabuta

Dear MASCOT-team 2 days after the landing of MASCOT on Ryugu, and analyzing the first data and images, it is time for me to thank all of your for an outstanding job.

When we started the MASCOT-project 7 years ago, it was clear that it will become hard work to build, to integrate, and to test a small lander equipped with 4 instruments in only 2 1/2 years time. I know that all of you had been engaged very much over a long time before launch and later during cruise phase for landing preparation. I like to thank all of you, and in particular our colleagues and partners in JAXA and CNES, for this work which made a small spacecraft landing a great event in space. To my knowledge of today, all systems worked nicely and made it possible to record as scheduled which demonstrated a careful and high quality work of all contributors as well as a great team spirit.

I am sure that the data recorded during the 17 hours operation on Ryugu's surface will become the basis of important scientific results. Thank you again!

With regards Hansjoerg Dittus

Message from Hansjörg Dittus, DLR Executive Board Member for Space Research and Technology

MASCOT press conference

MASCOT's Path on the Asteroid Ryugu Friday, October 12, 2018, 10:30am DLR Capital Office Berlin

3. Touchdown rehearsal and plan ■Re-examination of future operations  So far, 6 descent operations have been performed. Based on the performance of the navigation guidance and the surface of Ryugu, the revised schedule is as follows:

Note Descent operations: BOX-C operation, medium altitude operation, gravity measurement operation, TD1-R1 (first touchdown (TD) rehearsal), MINERVA-II operation, MASCOT operation.

■New Schedule  Oct. 14- 15 TD1-R1-A equivalent to the second TD rehearsal)  Oct. 24 - 25 TD1-R3 equivalent to the third TD rehearsal)  Late Nov - Dec Conjunction operation  After Jan 2019 First touchdown

The operation schedule after January 2019 will be determined based on the results up to TD1-R3.

(Note There is no TD-R2

Story so far:   Jul. 17 25 BOX-C operation → hovering at approximately 6km altitude   Jul. 31 Aug. 2 Medium altitude operation → down to approximately 5km altitude using GCP-NAV   Aug. 5 10 Gravity measurement operation → descent to 851m altitude   Aug 17 LSS based on current observation data (LSS: Landing site Selection)   Sep. 10 12 TD1-R1 → descent stopped at 600m altitude

Error in LIDAR laser altimeter measurement LRF Laser Range Finder could not be confirmed

  Sept. 19 21 MINRVA- 1 separation operation → descent to 55m altitude LIDAR measurement confirmed to have no problem High resolution observation data of TD candidate area obtained from navigation guidance data.

  Sept. 30 Oct. 4 MASCOT separation operation → descent to 51m altitude. High resolution observation data of TD candidate area obtained from navigation guidance data.

Basic policy for touchdown Proceed by confirmed each step one-by-one

3. Touchdown rehearsal and plan

MINERVA-II1 descent

MASCOT descent

TD1-R1 descent rehearsal #1

Trajectory of low altitude descents so far ©JAXA

  TD1-R1 descended to the equator, MINERVA-II1 operation was in the northern hemisphere and the MASCOT operation was in the southern hemisphere.

  Hayabusa2’s guidance was confirmed to have an accuracy of about 10m down to an altitude of about 50 over the entire latitude ±30°

N

S

Current results and information (1) Navigation guidance accuracy


Current results and information (2) Ryugu topology

Data as of August Current data

  From observations so far, the distribution of boulders about 50cm or larger has been determined for the TD candidate sites L08 L07 M04

  There are many boulders in the class larger than 50cm that hinder landing safely in the landing candidate area. Flat areas most suitable for landing are extremely limited.

30m



  Detailed analysis of surface conditions from images taken by MINERVA-II1 and MASCOT

  The images do not show a landscape of “sand interspersed with boulders” but rather “the ground itself consists of large and small rocks”.

Current results and information (3) Surface observations by rover and lander

©JAXA ©MASCOT/DLR/JAXA


Checklist before touchdown: Overcoming severely rugged topology, confirmation of the

spacecraft at ultralow altitude

  Navigation guidance accuracy down to an altitude lower than 50m check during TD1-R1-A

  Operation characteristics of LRF check during TD1-R1-A   Target marker (TM) tracking characteristics ← confirm during

TD1-R3 if possible Previous plans did not plan to check the TM tracking characteristics, but

this independent advance check was introduced in the new plan. After confirming these points, introducing pinpoint touchdown technology will also be considered. (see reference page)


Note : Target marker tracking (TMT) Target markers are recognized in images obtained by the optical navigation camera. The spacecraft understands the locations of the target markers and navigates itself for touchdown.

■ Plan during TD1-R1-A  Confirmation of navigation accuracy.  Understand characteristics of LRF.  LRF only performs a measurement and is not used here for spacecraft control.

■ Plan during TD1-R3  Confirmation of navigation accuracy.  LRF measurement data used for spacecraft control.  Potentially separate target markers (TM).


Touchdown candidate side L08-B



L08-B images by the ONC-T during the MASCOT separation operation. Image data Oct. 3, 2018, 05:41 JST. Image altitude: ~1.9km Resolution 20cm/pixel

L08-B



Close-up of previous page image

L08-B

20m diameter


L08-B images by the ONC-T during the MASCOT separation operation. Image data Oct. 3, 2018, 05;41 JST. Image altitude: ~1.9km Resolution 20cm/pixel (Image credit: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, Aizu University, AIST.)

TD1-R1-A schedule

©JAXA

Altitude

Time (JST)

Home position 20km

5km

~40m

10/14 ~24:00

10/16

Return to home position

10/15 ~10:00

10/15 ~22:30

Deceleration ΔV

ΔV

GCP-NAV (Ground Control Point Navigation) →Method of determining the position and speed

of the spacecraft by observing characteristic points on the asteroid surface.

HPNAV (Home Position Navigation) →Method of determining the position and speed

of the spacecraft from direction of the center of the asteroid image and attitude of the probe.


4. Future plans

■Operation schedule  Oct. 14 – 15 TD1-R1-A 2nd touchdown rehearsal

 Oct 24 - 25 TD1-R3 3rd touchdown rehearsal

■Media briefings

 Oct 23 (Tue) 16:00 JST Reporter’s presentation @ Ochianomizu  Nov 8 (Thur) 11:00 JST11 Press briefing @ Ochianomizu

Reference

3. MASCOT release operation

MASCOT (Mobile Asteroid Surface Scout)

Flight Model (© DLR)

(© JAXA)

  Developed by DLR (German Aerospace Center) in close cooperation with CNES (French Space Agency)

  Agile, lightweight & compact landing platform for in-situ asteroid research

  Lander Module mass: ~9.8 kg

  Lander Module size: 0.275 x 0.290 x 0.195 m

  Carries Four Scientific Payloads: MASCAM, MicrOmega, MARA, and MASMAG

MASCOT System Overview


Device Func�on

Wide-‐angle camera (MASCAM) Imaging at mul�ple wavelengths

Spectroscopic microscope (MicrOmega)

Inves�ga�on of mineral composi�on and characteris�cs

Thermal radiometer (MARA) Surface temperature measurements

Magnetrometer (MASMAG) Magne�c field measurement

Scientific instruments aboard MASCOT

MASCOT Bus System   Power: Primary lithium battery   Communication: Communication system using

transceivers same as Minerva-II rovers   Mobility: Up-righting and hopping mechanism

using motor and excenter mass   GNC: MASCOT attitude determination using

proximity sensors

MARA

MASCAM

MicrOmega MASMAG

Ebox

Mobility Unit

Battery Pack

CCOM Transceivers

Radiator Top Antenna MASCOT System Overview


CP : Contact Point EoM : End of Mission SP : Se�lement Point MP : Measuring Point MSC : MASCOT

Baseline MASCOT Activities after the Separation

MASCOT On-Asteroid Operation


©JAXA, University Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST, CNES, DLR

MASCOT landing site

  Use of multiple TM

ü We will touch down near the artificial crater, and attempt to retrieve samples from exposed areas.

ü We expect the artificial crater to have a diameter of around several meters. By approaching the destination point based on clues from multiple sequential TM, we can perform the touchdown with higher precision (a pinpoint touchdown).

Pinpoint touchdown  Target Markers (TM)

ü TM separate at an altitude of several tens of meters, and flash lamps intermittently illuminate TM while cameras image them.

ü By comparing differences in images when flash lamps are lit and when they are not, we can accurately extract TM without effects from surface patterns or sunlight.

ü Facing toward identified TM, descend to the asteroid while using laser altimeter information to determine attitude and distance to the surface.

ü 6-degree-of-freedom (position + attitude) gas jet injection control with high target tracking while minimizing fuel consumption is also a key technology.

(© JAXA)

Using one TM Using multiple TM

Crater

First descent

Second descent Third

descent

Range of error for descent to TM #3 with TM #2 visible

Range of error with no other TM for use as clues

Range of error for descent to TM #1

Range of error for descent to TM #2 with TM #1 visible

Conjunction operation

 “Conjunction” for spacecraft operation refers to the case where the spacecraft is in the direction that almost directly overlaps with the Sun when viewed from Earth.

  The alignment means that communication with the spacecraft is not secure due to radiowaves radiated by the Sun.

 In this period, critical operation is not carried out.

 For Hayabusa2, the duration of this period is from late November 2018 – end of December.

Earth

Ryugu

Sun

2018.11.20

2018.12.31

Positions of Ryugu and the Earth

©JAXA

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